CRLF Injection Vulnerability in LibreSSL Affected by Unvalidated Request Paths
CVE-2026-118371

6.3MEDIUM

Key Information:

Vendor

OpenBSD
Status
Libressl
Vendor
CVE Published:
28 October 2026

What is CVE-2026-118371?

LibreSSL versions up to 4.4.0 are susceptible to a CRLF injection vulnerability stemming from the functions OCSP_sendreq_new() and OCSP_parse_url(). This flaw allows attackers to manipulate the Authority Information Access OCSP URI by embedding carriage return and line feed characters, which can lead to the injection of unauthorized HTTP headers or cause the splitting of requests directed at responders and proxies. Such exploits can significantly compromise the integrity of communication over networks that rely on OCSP for certificate validation.

Affected Version(s)

LibreSSL 0 <= 4.4.0

References

https://github.com/openbsd/src/commit/d3f7195f4849d8a699c...
patch
https://github.com/openbsd/src/blob/3903c41d301d66facec69...
technical-description
https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-4.4...
release-notes

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Aziz Elbelaychy (Ostorlab)
Theo Buehler
.